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How to Manage Pests
UC Pest Management Guidelines
Floriculture and Ornamental Nurseries
Twospotted Spider Mites
Scientific name: Tetranychus urticae
(Reviewed 1/04,
updated 1/04)
In this Guideline:
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DESCRIPTION OF THE PEST
Twospotted spider mites are web-forming mites that pierce plant cells and
remove their contents. All spider mites have two body segments and four pairs
of legs as adults. Twospotted spider mite
adults, as the name suggests, have two
large dark spots on the sides of their yellowish green bodies. These mites lay
round eggs that hatch into six-legged larvae. The subsequent stages, the
protonymph and deutonymph stages, are eight-legged as are the adults. Since the
entire life cycle can take as little as 8 (77° to 95°F) to 28
(50° to 68°F) days, spider mites have many generations per year and
can rapidly increase in number.
DAMAGE
Twospotted mites suck cell contents from leaves, initially stippling leaves
with a fine pale green mottling. As feeding continues, the stippling increases
and leaves turn yellow with bronzed or brown areas; damaged leaves frequently
fall. Undersides of leaves may have many cast skins of mites, and the
webbing on foliage is unaesthetic.
Plants may become severely stunted when large mite populations are allowed to
feed and the plants may die.
BIOLOGICAL CONTROL
Many different species of predatory
mites are available for control of these mites under different conditions.
Phytoseiulus persimilis is a commercially available predator of
twospotted spider mite, and it has been used to control mite populations in
greenhouses and field situations. It can reproduce faster than its prey, yet
best results have been obtained when it is released into the crop well before
the spider mite populations have built up.
CULTURAL CONTROL
Because spider mites feed on a large variety of plants, keep production areas
free of weeds, which can serve hosts to the mites. Carefully inspect plants
being brought in to start a new crop to ensure that they are free of mites.
Rogue or treat infested plants.
MONITORING and WHEN TO TREAT
Monitor the crop regularly, as indirect sampling methods (such as sticky cards)
are ineffective. Observe the undersides of leaves with a 10X hand lens, and
watch for changes in plant foliage, which is characteristic of mite feeding.
Except as noted, the materials listed only kill active stages of mites, so more
than one treatment may be necessary to break the life cycle. Follow label
directions regarding reapplication times.
TREATMENT
Selected Materials Registered for Use on Greenhouse or Nursery Ornamentals
Read and follow the instructions on the label before using any pesticide.
Before using a pesticide for the first time or on a new crop or cultivar, treat
a few plants and check for phytotoxicity.
| Class |
|
Pesticide (commercial name) |
Manufacturer |
R.E.I.1 |
Comments |
| botanical |
A. |
cinnamaldehyde
(Cinnacure) |
Proguard |
4 |
Use product within 10 days of breaking seal. May cause
phytotoxicity to tender tissue growth on plants. After 2 applications, rotate
to an insecticide of a different chemistry for at least 2 applications. Do not
apply to stressed plants or newly transplanted material before roots are
established. Do not apply through any type of irrigation system. |
|---|
| carbamate |
A. |
methiocarb*
(Mesurol 75W) |
Gowan |
24 |
Apply in 50 gal water. Repeat as necessary up to 4
applications/season. Do not apply with oil or foliar fertilizer. Do not use
through any type of irrigation system. |
|---|
| carboximide |
A. |
hexythiazox
(Hexygon 50WP) |
Gowan |
12 |
No chemigation. Ovicidal/larvicidal action. Use only 1 time per
crop or once a year. |
|---|
| carboxylic acid |
A. |
bifenazate
(Floramite) |
Uniroyal |
12 |
Do not use in successive applications; apply at least two
alternative products between treatments of bifenazate. Primarily effective
against motile stages but has some ovicidal activity. |
|---|
| macrocyclic lactone |
A. |
abamectin
(Avid 0.15EC) |
Novartis |
12 |
Label permits low-volume application. |
|---|
| oil2 |
A. |
clarified hydrophobic extract of neem oil
(Triact 70) |
Certis |
4 |
Do not spray plants under stress. Target pest must be
completely covered with spray. Check label for list of plants that can be
treated. May cause injury to flowers. Do not use through any type of irrigation
system. |
|---|
| B. |
horticultural oil
Ultra-Fine Oil
SafTSide
JMS Stylet Oil |
Whitmire MicroGen
Brandt
JMS Farms |
4
4
4 |
Use as above for neem oil. Also, do not use with sulfur fungicides; check label for tank mix restrictions. |
|---|
| organochlorine |
A. |
endosulfan*
(Endosulfan 3EC) |
Gowan |
24 |
Check local water/runoff restrictions. Some varieties of
chrysanthemum exhibit phytotoxicity. Do not use through any type of irrigation
system or apply more than 3 lb a.i./ acre/season. |
|---|
| B. |
dicofol
(Kelthane 50WP) |
Dow AgroSci |
48 |
Also labeled for low-volume use. Do not use through any type of
irrigation system. |
|---|
| organtin |
A. |
fenbutatin-oxide
(Vendex) |
Griffin Corp |
48 |
|
|---|
| phenoxypyrazole |
A. |
fenpyroximate
(Akari) |
SePRO |
12 |
Do not apply more than 10 gal spray/1000 sq ft/application. Do
not exceed 48 oz/crop cycle or growing season, whichever is longer. |
|---|
| pyrethroid |
A. |
bifenthrin*
(Attain TR) |
Whitmire
MicroGen |
12 |
Check label. A fogger for greenhouse use only. |
|---|
| B. |
bifenthrin*
(Talstar Flowable) |
Whitmire
MicroGen |
12 |
Label permits low-volume application. |
|---|
| C. |
fenpropathrin*
(Tame 2.4EC Spray) |
Valent |
24 |
Label permits low-volume application. Do not use through any
type of irrigation system. |
|---|
| D. |
fluvalinate
(Mavrik Aquaflow) |
Wellmark |
12 |
Label permits low-volume application. Also labeled as a cutting
dip at 5 fl oz/100 gal. Do not use through any type of irrigation system. |
|---|
| pyridazinone |
A. |
pyridaben
(Sanmite 75WP) |
BASF |
12 |
Use at least 2 different chemical between application of
Sanmite. Do not use fertilizers containing boron or apply through any type of
irrigation system. Do not exceed 10.67 oz/acre/application. |
|---|
| pyrrole |
A. |
chlorfenapyr
(Pylon) |
Olympic |
12 |
Greenhouse use only. Do not exceed 3 applications/growing cycle. |
|---|
| soap2 |
A. |
potash soap
(Insecticidal soap)
(M-Pede) |
Olympic
DowAgro |
12
12 |
Must contact insect, so thorough coverage is important. Repeat weekly as needed
up to 3 times. Test for phytotoxicity. Do not spray new transplants or newly
rooted cuttings. Do not add adjuvants. |
|---|
| spinosyn |
A. |
spinosad
(Conserve SC) |
Dow Agro-sciences |
4 |
Miticidal activity of this material is due mainly to the
surfactants and other inert ingredients. This material is not recommended for
use against mites unless control is also needed for other pests (caterpillars,
leafminers, thrips) against which the active ingredient in this product is
effective. Do not apply more than 10 times in a 12-month period. Do not apply
more than 3 times in a row without rotating to a material with different
chemistry. Compatible with most beneficials but highly toxic to bees and
hymenopteran parasites. Direct contact can cause significant mortality to
Phytoseiulus persimilis. |
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UC IPM Pest Management Guidelines: Floriculture and Ornamental Nurseries
UC ANR Publication 3392
Insects and Mites
K. L. Robb, UC Cooperative Extension, San Diego Co.
H. S. Costa, Entomology, UC Riverside
J. A. Bethke, Entomology, UC Riverside
M. P. Parrella, Entomology, UC Davis
Acknowledgment for contributions to the insects and mites section:
R. S. Cowles, Connecticut Agricultural Experiment Station, Windsor, CT
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